scholarly journals Field Performance and Rapid Repair Method of an Airfield Pavement under the Blast Load of Cluster Bomb Unit

2021 ◽  
Vol 1203 (3) ◽  
pp. 032070
Author(s):  
Injae Hwang ◽  
Sungkon Kim
Keyword(s):  
Penetration Depth ◽  
Field Test ◽  
Concrete Slab ◽  
Field Performance ◽  
Free Fall ◽  
Test Site ◽  
Crushed Stone ◽  
Blast Load ◽  
Repair Method ◽  
Cluster Bomb

Abstract This paper discusses a field test of airfield pavement under cluster bomb unit (CBU) blast load and a study of repair method upon the examination of the damage geometry. Cluster bomb unit blast load shows a similar level to that of a typically known air-to-ground munition, and the penetration depth was calculated using empirical formulae with terminal velocity during a free fall following an explosion and dispersion 20km above the ground. Based on the calculations, the field test was executed assuming a cluster bomb unit penetration depth of 33cm for concrete pavement surface. The concrete slab on the test site was casted in a circular shape at the field and then cured. This slab was an unreinforced concrete structure with a similar compressive strength and thickness as that of airfield pavement currently in use. The test reflected the cluster munition penetration depth of 33cm, and the concrete slab was drilled in the center and explosive with a weight resembling that of the cluster munition installed. As results of the blast test show a damage to the pavement expanded the crater to a depth of 78cm, down to the crushed stone layer and with a diameter of 30cm. The concrete fragmentation requiring removal was of about 156cm in radius on average. The 7 tensile cracks across the pavement were not so heavily damaged to require removal. Cutting and removing the crushed concrete slab with dimension of 1.8m × 1.8m, compacting the disturbed crushed stone layer and repairing the concrete slab section using ultra-rapid hardening concrete are reviewed the appropriate repair method based on the above results.

Field testing and probabilistic assessment of ballistic penetration of steel plates for small calibre military ammunition

2018 ◽  
Vol 10 (4) ◽  
pp. 421-438 ◽  
Author(s):  
Mark G Stewart ◽  
Brianna Dorrough ◽  
Michael D Netherton
Keyword(s):  
Penetration Depth ◽  
Field Test ◽  
Predictive Models ◽  
High Strength ◽  
Field Testing ◽  
Hardened Steel ◽  
Steel Plates ◽  
Probabilistic Assessment ◽  
Test Results ◽  
Terminal Ballistics

The penetration of projectiles into semi-infinite targets helps in the understanding and modelling of terminal ballistics. The article describes field test results of 5.56×45 mm F1 Ball and 7.62×51 mm M80 Ball ammunition. The targets were 25-mm-thick mild and high strength steel plates of Grade 250 MPa and 350 MPa, respectively. The tests recorded penetration depth, muzzle and impact velocities, and bullet mass. Despite its smaller calibre, the 5.56 mm × 45 mm F1 Ball ammunition recorded deeper penetrations than the larger calibre 7.62 mm × 51 mm M80 Ball ammunition. This is due to the 5.56 mm ammunition comprising a hardened steel penetrator and lead core, whereas the 7.62 mm ammunition comprised only a lead core. Multiple shots were fired for each type of munition. The coefficient of variation of steel penetration is approximately 0.10 and 0.03 for 5.56 mm and 7.62 mm rounds, respectively. The article also presents predictive models of steel penetration depth and compares these to the field test results.

Design and Field Test of a New Compact Self-Propelled Cabbage Harvester

2019 ◽  
Vol 62 (5) ◽  
pp. 1243-1250 ◽  
Author(s):  
Dongdong Du ◽  
Jun Wang ◽  
Luxin Xie ◽  
Fanfei Deng
Keyword(s):  
Field Test ◽  
Field Tests ◽  
Field Performance ◽  
Performance Tests ◽  
Cultivation Method ◽  
Compact Field ◽  
Cutting Rate ◽  
Traditional Fields ◽  
Mechanical Harvester

Abstract. As a labor-intensive operation, manual harvesting greatly affects cost and therefore profitability in the cabbage industry. A new compact self-propelled cabbage harvester for small, separate fields was designed and field tested. This harvester included a crawler chassis, a picking mechanism, a lifting mechanism, a cutting device, and a leaf separator. Results of preliminary field tests showed that the harvester had good flexibility and maneuverability. Results of field performance tests showed that the harvester could pick cabbages with diameters of 15 to 25 cm, providing a harvesting capacity of 0.21 hm2 h-1 and a harvest loss of 10.2%. Compared with experiments conducted in traditional fields, harvest quality showed an improvement in fields with an experimental cultivation method. The harvest loss was reduced by 5.0%, while the picking rate and accurate cutting rate were improved by 3.0% and 5.4%, respectively. Keywords: Cabbage, Compact, Field test, Mechanical harvester, Self-propelled.

MAJOR FIELD TEST EVALUATES A SHORELINE CLEANER TO SAVE OILED MARSH GRASS

1997 ◽  
Vol 1997 (1) ◽  
pp. 397-402 ◽  
Author(s):  
S. R. Pezeshki ◽  
R. D. DeLaune ◽  
A. Jugsujinda ◽  
G. P. Canevari ◽  
R. R. Lessard
Keyword(s):  
Spartina Alterniflora ◽  
Field Test ◽  
Field Tests ◽  
Field Studies ◽  
Test Site ◽  
Field Conditions ◽  
Marsh Vegetation ◽  
Beneficial Effects ◽  
Live Biomass ◽  
South Louisiana

ABSTRACT Extensive greenhouse studies using intact cores of marsh vegetation including Spartina alterniflora demonstrated the potential of a shoreline cleaner (Corexit 9580) to remove oil from plant canopy. Because of these positive results, a permit to conduct a full-scale field test was obtained by Louisiana State from regulatory agencies in June 1995. Field tests were conducted in a Louisiana marsh at a wildlife refuge in August 1995. The test site contained replicated 8 ft X 8 ft test plots that included the following treatments: oiled with South Louisiana crude oil, oiled and chemically cleaned after 2 days using Corexit 9580, and control. Significant initial reductions in plant stomatal conductance, transpiration, and CO2 fixation rates in response to the “oil” and “oil + Corexit 9580” treatments were noted, which were followed by substantial recovery in the “oil + Corexit 9580” treatment. Use of the cleaner improved the survival and regeneration capability of treated plots because of the low initial mortality rates and the rapid restoration of plant gas exchange activities. Plots treated with “oil + Corexit 9580” had a significantly greater number of live shoots throughout the measurement period in 1995. Biomass harvests conducted at the end of the 1995 growing season revealed that live biomass per unit area of marsh was significantly reduced under all treatments. The second harvest in 1996 indicated that live biomass had recovered to levels close to those of control plots. Our field studies demonstrated that oil can be removed using Corexit 9580 in the field without any detectable adverse effects on plants, In addition, the beneficial effects of Corexit 9580 in rapidly restoring plant transpiration pathways under field conditions was evident. However, plants under all treatments recovered, showing that Spartina alterniflora, given adequate time, can recover from oiling with South Louisiana crude. Additional studies using more stressful oil types such as Bunker C are needed to examine the effectiveness of Corexit 9580 in cleaning plant canopies under field conditions.

On Test Uncertainties in Field Performance Tests

2015 ◽  
Author(s):  
Rainer Kurz ◽  
Klaus Brun
Keyword(s):  
Measurement Uncertainty ◽  
Gas Turbine ◽  
Field Test ◽  
Measurement Errors ◽  
Equations Of State ◽  
Accurate Determination ◽  
Field Performance ◽  
Significant Implication ◽  
Test Results

Field testing of gas turbine or electric motor driven compressor packages requires the accurate determination of efficiency, capacity, head, or power consumption in sometimes less than ideal working environments. Nonetheless, field test results have significant implication for the compressor and gas turbine manufacturers and their customers. Economic considerations demand that the performance and efficiency of an installation are verified to assure the return on investment for the project. Thus, for the compressor and gas turbine manufacturers, as well as for the end-user, an accurate determination of the field performance is of vital interest. This paper discusses a method to determine the measurement uncertainty and, thus, the accuracy, of test results under the typical constraints of a site performance test, for compressors capable of variable speed operation. Namely, a method is presented which can be employed to verify the validity of field test performance results. Results are compared with actual field test results, using redundant methods. Typical field test measurement uncertainties are presented for different sets of instrumentation. The effect of different equations of state on the calculated performance is also discussed. Test parameters that correlate to the most significant influence on the performance uncertainties are identified and suggestions are provided on how to minimize their measurement errors. Results show that compressor efficiency uncertainties can be unacceptably high when some basic rules for accurate testing are violated. However, by following some simple measurement rules and maintaining commonality of the gas equations of state, the overall compressor package performance measurement uncertainty can be limited and meaningful results can be achieved.

Penetration Depth Analysis of K307 Cannonballs Colliding into Sand of Various Shear Moduli

2014 ◽  
Vol 711 ◽  
pp. 104-107
Author(s):  
Yoon Keon Kim ◽  
Woo Chun Choi
Keyword(s):  
Shear Modulus ◽  
Penetration Depth ◽  
Test Site ◽  
Economic Feasibility ◽  
Good Stability ◽  
Shear Moduli ◽  
Depth Analysis ◽  
Small Grains ◽  
Test Side ◽  
A Site

In order to test the performance of a cannonball, various types of media are used in a test site. The best media should have good stability, effectiveness, economic feasibility, etc. Among them, sand is most widely used. Sand, which consists of many small grains, can be used effectively in a site. In this study, the penetration depth of a cannonball is analyzed for shear modulus using FEM. It is found that the penetration depth decreases with the shear modulus of sand. For management of a test side, the shear modulus of sand is an important factor.

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